One of the problems of drug abuse facing the scientific community concerns keeping apace with apperance of new compounds subject to illicit use. Since the late 1960's there has been an increasing abuse of a new class of compounds represented principally by phencyclidine (PCP). PCP was originally developed as an anesthetic, but at lower doses produces a unique spectrum of psychological effects which users find reinforcing. There is now evidence that some individuals abuse this drug chronically. We propose to study the behavioral pharmacology of PCP in four species of laboratory animals, mice, rats, squirrel monkeys and rhesus monkeys. We will study the acute effects of PCP on a wide variety of behavioral measures, but will focus on schedule-controlled operant behavior. We will study tolerance and dependence development, and the interaction between PCP and other drugs of abuse. We will also study the effects of some PCP analogues. The intravenous self-administration of PCP will also be investigated in rhesus monkeys.